U.S. patent application number 13/359254 was filed with the patent office on 2012-09-20 for method for manufacturing a sheet product for use in a dispenser and strip of sheet product.
This patent application is currently assigned to GEORGIA-PACIFIC CONSUMER PRODUCTS LP. Invention is credited to Ann M. Andres, Abby C. Case, Gilles Cattacin, Pierre Laurent, Julien Marietta-Tondin, Remy Ruppel.
Application Number | 20120237711 13/359254 |
Document ID | / |
Family ID | 38038569 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120237711 |
Kind Code |
A1 |
Cattacin; Gilles ; et
al. |
September 20, 2012 |
Method for Manufacturing a Sheet Product for Use in a Dispenser and
Strip of Sheet Product
Abstract
The invention relates to a method of manufacturing a web of
sheet product, with a discontinuous perforation arrangement such
that manufacture of a web of sheet product provides for an increase
in the breaking strength of the web of sheet product while feeding
the web in a machine direction, thereby reducing the risk of
breaking and maintaining the yield and throughput of the production
of the perforated web as an intermediate product, yet providing a
low breaking force for individual strips produced from the web.
Inventors: |
Cattacin; Gilles; (Colmar,
FR) ; Laurent; Pierre; (Turckheim, FR) ;
Marietta-Tondin; Julien; (Marckolsheim, FR) ; Ruppel;
Remy; (Durrenentzen, FR) ; Andres; Ann M.;
(Neenah, WI) ; Case; Abby C.; (Green Bay,
WI) |
Assignee: |
GEORGIA-PACIFIC CONSUMER PRODUCTS
LP
Atlanta
GA
|
Family ID: |
38038569 |
Appl. No.: |
13/359254 |
Filed: |
January 26, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12513004 |
Apr 30, 2009 |
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PCT/FR07/01737 |
Oct 22, 2007 |
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13359254 |
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Current U.S.
Class: |
428/43 ;
493/369 |
Current CPC
Class: |
B65H 2551/15 20130101;
B65H 33/00 20130101; Y10T 83/483 20150401; A47K 10/3612 20130101;
B65H 45/18 20130101; B31D 1/0031 20130101; B65H 31/02 20130101;
B26F 1/20 20130101; B31D 1/04 20130101; B65H 31/10 20130101; B65H
31/3009 20130101; B65H 45/142 20130101; B65H 2551/29 20130101; B65H
33/18 20130101; Y10T 83/0515 20150401; B65H 2405/11152 20130101;
B65H 2701/1924 20130101; B65H 2405/11151 20130101; B65H 45/28
20130101; B65H 2551/14 20130101; Y10T 428/15 20150115; A47K 10/16
20130101; A47K 10/42 20130101 |
Class at
Publication: |
428/43 ;
493/369 |
International
Class: |
B32B 3/24 20060101
B32B003/24; B31B 49/00 20060101 B31B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2006 |
FR |
06/09546 |
Claims
1. Method of manufacturing a web of sheet product, comprising the
steps of: feeding a web of sheet product in a machine feeding
direction, the web being multiple widths of sheet product in
breadth; creating perforations in the web of sheet product along a
perforation line transverse to the machine feeding direction, so
that a perforation is formed having a repeating pattern of cut
portions and non-cut portions; cutting the web into strips of sheet
product after creating perforations along the machine feeding
direction, each strip having a predetermined width; wherein the web
in the step of creating perforations is partially perforated along
the perforation line, so that at least one perforated segment
provided with the perforation and at least one non-cut segment are
alternately arranged along the perforation line, wherein each of
the at least one perforated segments is associated to one or more
strips to be produced and arranged on the web, such that the
cutting of the web results in strips having a perforation along the
width of each produced strip, and wherein at least one perforated
segment has a length greater than and extends across the width of
strip with at least one end of the at least one perforated segment
extending into the material of web that corresponds to an adjacent
strip of sheet product, so that the step of cutting the web results
in strips having a perforated side-cut at least at one edge of the
strip between two spaced perforation lines of the respective
strip.
2. Method according to claim 1, wherein a plurality of perforation
lines are cut which are spaced in the machine feeding direction,
wherein at least one perforated segment and at least one non-cut
segment are staggered.
3. Method according to claim 1, wherein the length of the non-cut
segment is larger by a factor of at least 2 than a sum of the
lengths of the non-cut portion in an adjacent perforation
segment.
4. Method for manufacturing strips of sheet product, in particular
for use as paper towels, napkins, hand tissues, facial tissues,
toilet papers, kitchen towels, hand towels, wipers, placemats, and
the like, wherein a web of sheet product is manufactured according
to claim 1, and wherein the length of the perforated segments is
selected such that the collective length of the at least one
perforated side-cut is between 1% to 20%, and more desirably 2% to
20%, of the width of each strip of sheet product.
5. Method according to one of the claim 1, wherein a bond ratio of
the perforated segment is equal to or less than 15%.
6. Method according to claim 5, wherein at least one end of the
perforated segment has a fading perforation portion that has a
higher bond ratio than the rest of the perforated segment.
7. Method according to claim 5, wherein at least one end of the
perforated segment has a fading perforation portion that has a
lower bond ratio than the rest of the perforated segment.
8. Method according to claim 5, wherein the web is provided with a
separation perforation after the step of creating perforations in
the web of sheet product along a perforation line, wherein the
separation perforation has a bond ratio that is adapted to have a
total breaking strength which is lower than the total breaking
strength of the perforation line.
9. Method according to claim 1, wherein the web is reeled up to
form a log of sheet product after the step of creating perforations
in the web of sheet product along a perforation line, wherein the
step of cutting is performed by severing the log to obtain rolls of
sheet product.
10. The method according to claim 1, wherein the web machine feed
speed is at least 300 ft/min.
11. The method according to claim 1, wherein the predetermined
sheet widths are not equal.
12. A web of sheet product having spaced perforation lines
transverse to its longitudinal orientation, wherein along each
perforation line the web has at least one perforated segment and at
least one non-cut segment that are alternately arranged along the
perforation line, wherein the at least one perforated segment has a
perforation with a repeating pattern of cut portions and non-cut
portions, and wherein the web has a breadth of at least three
strips, each strip having a predetermined width, wherein each
perforated segment is associated with one or more of the strips to
be disposed from the web, at least two adjacent perforated segments
along the same perforation line extending across the respective
strip width of web in a direction transverse to the longitudinal
extension, and further extending along the web of sheet product to
create perforated side-cuts, wherein the perforated side-cuts have
a length of between 1% to 25% of the predetermined strip width.
13. The web according to claim 12, wherein the web is provided with
a separation perforation, wherein the separation perforation has a
bond ratio that is lower than the bond ratio of the perforated
segment.
14. The web according to claim 12, wherein the web is manufactured
at a web fed rate of at least 300 ft/min.
15. The method according to claim 12, wherein the predetermined
sheet widths are not all the same.
16. A source of sheet product for use in a dispenser, including a
strip of sheet product having sheets connected at an unbroken
perforation line, wherein along the longitudinal extension of the
strip perforated side-cuts are provided at least at one edge of the
strip.
17. Source of sheet product according to claim 16, wherein the
perforated side-cuts are arranged between two spaced perforation
lines along the longitudinal extension of the strip.
18. Source of sheet product according to claim 16, wherein the
perforated side-cuts have a combined length of between 1% to 25% of
the width of each strip of sheet product.
19. Source of sheet product according to claim 16, wherein the
perforated side-cuts have a bond ratio equal to or less than the
bond ratio of the perforated line from which it extends.
20. Source of sheet product manufactured by the method according to
claim 5.
21. Source of sheet product according to claim 16, wherein the
strip of sheet product is wound to form a roll.
22. Source of sheet product according to claim 16, wherein the
strip of sheet product is folded along its longitudinal extension,
so that the sheets are stacked onto each other to form a sheet
stack.
23. The method of claim 1, wherein the perforation line extends
across the entire width of the width of the strip.
24. The web of claim 12, wherein the perforation line extends
across the entire width of the width of the strip.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of
U.S. patent application Ser. No. 12/513,004, filed on Apr. 30,
2009, which is the national stage entry of International
Application No. PCT/FR2007/001737, filed on Oct. 22, 2007, which
claims priority to French Application No. 06 09546, filed on Oct.
31, 2006 (now French Patent No. 2907654), the priorities of which
are hereby claimed and their disclosures incorporated in their
entireties herein by reference.
TECHNICAL FIELD
[0002] The present application generally relates to a method for
efficiently manufacturing a strip of sheet product for use in
dispensers, in particular for manufacturing rolls of an absorbent
or non-absorbent product, such as paper towels, napkins, hand
tissues, facial tissues, toilet papers, kitchen towels, wipers,
placemats, and the like. Furthermore, the present application
relates to a strip of sheet product for use in a dispenser.
RELATED ART
[0003] Manually operated dispensers for dispensing a sheet product,
such as paper wipes, paper hand towels, bathroom tissues and the
like, usually comprise a housing in which a source of the sheet
product, e.g., a tissue paper roll or a tissue paper stack of a
continuous strip of paper, is accommodated. In the case of the
roll, the source of sheet product is a wound continuous strip of
sheets. The single sheets constituting the roll are often connected
to each other at perforation lines or precuts.
[0004] The housing of such a manually operated paper sheet
dispenser usually comprises an opening to guide the loose end of a
paper roll to the exterior of the housing. A user that intends to
remove one or more paper sheets from the dispenser pulls at the
loose end of the paper strip, i.e., an end sheet, until one of the
perforation lines comes into a position in which the pulled paper
sheet can be detached from the paper roll, for example by a quick
tug. The dispenser opening of the manually operated dispenser can
be slit-like, such that a paper sheet can be pulled out as an
unfolded web and remains unwrinkled. Alternatively, the opening can
be formed as a cone-shaped mouth, wherein the strip is pulled
through a, e.g., substantially circular or oval opening, whereby
the constricted paper is folded or crumpled so as to form a loose
rope or rope-like form of paper. In each case, the sheets from the
paper roll that have passed through the opening of the manually
operated dispenser can be detached from the rest of the paper
source inside the housing by an increased manual force, such that
the paper sheet breaks at the perforation line that is closest to
the opening of the dispenser outside of the housing.
[0005] A pulling force has to be applied to the wound sheets of the
paper roll in order to pull them through the opening of the
dispenser, thereby overcoming friction that occurs when the paper
is unwound from the roll and guided through the opening. In order
to allow withdrawal of the paper from the dispenser, the sheets do
not break along a perforation line before the pulling force is high
enough to overcome the friction. Furthermore, it should be assured
that the sheets do not break along a perforation line that is still
within the housing, or else operation of the dispenser is
compromised and sheets are unavailable to the user.
[0006] When applying the pulling force, there is always the risk of
breaking of the paper, in particular, at the points where the
perforation lines separate the respective paper sheets. Hence, in
view of the frictional forces, the dispenser design is adapted to
the breaking strength of the paper strip and, in particular, to the
breaking strength of the perforation lines. In other words, the
breaking strength of the perforations defining a breaking force
threshold is generally significantly higher than the pulling force
that is required to pull the paper sheets out of the manually
operated dispenser.
[0007] For dispensers having a cone-shaped opening for dispensing
paper sheets, the overall friction applied to the paper strip which
must be overcome by the pulling action of the user is dominated by
the friction from the constricted opening. The necessary
perforation breaking force threshold of current sheets and
dispensers requires the user to pull the sheet with a significant
force, which can render the overall process of withdrawing a paper
sheet from the dispenser inconvenient.
[0008] Conventionally, in the manufacturing process of producing
strips of a sheet product for use in dispensers, a web of a sheet
product, such as a paper web, is processed in a continuous manner
using a cutting head to create a perforation line in the paper web
to be processed. The cutting head usually comprises a plain blade
and a patterned perforation blade in order to cut the perforation
across the full width of the paper web.
[0009] Usually, in order to increase the throughput of
manufacturing, the width of the web is larger than the width of the
paper rolls to be produced, such that after cutting the perforation
lines and winding the web onto a core, i.e., log forming, the log
is cut into parts to obtain paper rolls of a desired width.
Furthermore, the machine feeding speed applies a constant tension
force onto the fed web. Hence, the feeding speed is restrained to
avoid exceeding the breaking strength of the web while feeding.
[0010] The desire to reduce the breaking force threshold of the
perforation lines of the paper strip conflicts with the desire to
increase or maintain the machine feeding speed, and raises
significant issues in the manufacturing process. A high perforation
(i.e., low bond ratio) and resulting low breaking force threshold
could lead to breakage of the perforated paper web in the
manufacturing process when the paper web is transferred to the
reels to form a paper roll, especially when such a transfer is done
at high speed and/or tension.
[0011] Paper rolls having a higher density (e.g., more tightly
wound rolls) are generally desired in light of transportation and
dispenser size considerations. As the density of the sheet roll
reeled up on a log strongly depends on a tension of the paper web
in a feeding direction, the breaking force threshold defined by the
perforation lines should not fall below a certain threshold value
to avoid a low density of sheets in the paper rolls.
[0012] Hence, there is a balance between a minimum breaking force
threshold of the connected paper sheets implied by the
manufacturing constraints and the dispenser design that defines the
pulling force necessary to overcome the opposing force (e.g.,
friction) applied to the paper strip within the dispenser.
[0013] In document WO 2008/056042 A1, a method for producing a roll
is disclosed. The roll is made of a succession of single-use
absorbing paper sheets separated along at least one side thereof,
perpendicular to the unwinding direction of the roll, by parallel
precuts, the sheets being further separated by cuts extending along
at least 80% of the cut side of the sheets, and the cuts and
precuts alternating in the roll unwinding direction.
[0014] Document US 2009/0155512 A1 discloses a roll of a sheet
material with elongated sheets within the roll that are either
completely detached from each other or substantially completely
detached from each other, such that the user can dispense the
elongated sheets with one hand.
[0015] Furthermore, document US 2010/0075094 discloses a roll
comprising a succession of sheets of absorbent paper separated
along at least one of their sides perpendicular to a roll-unwinding
direction by mutually parallel precuts, wherein the sheets are also
separated by cuts, the cuts and precuts alternating in the
roll-unwinding direction.
[0016] Document US 6010090 discloses a method of perforating a web
along a plurality of transverse lines, the lines of perforations
being staggered; however, such perforations do not extend across
transverse planes which correspond to the longitudinal lines of the
web.
[0017] Document US 2053786 discloses a method of forming paper
rolls which are divided transversely; however, the paper is
connected only at one marginal edge by narrow ties so as to avoid
waste issues associated with the use of rolls not so completely
severed.
[0018] In view of the above issues, the present invention provides
a method for manufacturing a web and rolls of sheet product wherein
the ability to withstand breaking during the manufacturing process
is improved. Unlike conventional manufacturing methods, the
invention is not confined to slower manufacturing speeds for making
a paper web having such lower breaking forces.
SUMMARY OF THE INVENTION
[0019] These disadvantages are overcome by the method of
manufacturing a web of sheet product, the method of manufacturing
strips of sheet product, the web and the sheet product according to
the present invention. It shall be noted that the sheet products
may be absorbent or non-absorbent, such as paper towels, napkins,
hand tissues, facial tissues, toilet papers, kitchen towels,
wipers, placemats and the like. Other sheet products also can be
made according to the present invention, irrespective of
absorbency, including non-wovens, films (including polymeric film),
and foil (including metallic film).
[0020] According to a first aspect a method for manufacturing a web
of sheet product is provided. The method includes the following
steps: [0021] feeding a web of sheet product in a machine feeding
direction, the web being multiple widths of sheet product in
breadth; [0022] creating perforations in the web of sheet product
along a perforation line transverse to the machine feeding
direction, so that a perforation is formed having a repeating
pattern of cut portions and non-cut portions; [0023] cutting the
web into strips of sheet product after creating perforations along
the machine feeding direction, each strip having a predetermined
width; [0024] wherein the web is partially perforated along the
perforation line, so that at least one perforated segment provided
with the perforation and at least one non-cut segment are
alternately arranged along the perforation line, [0025] wherein
each of the at least one perforated segments is associated to one
or more strips to be produced and arranged on the web, such that
the cutting of the web results in strips having a perforation along
the width of each produced strip, and [0026] wherein at least one
perforated segment has a length greater than and extends across the
width of strip with at least one end of the at least one perforated
segment extending into the material of web that corresponds to an
adjacent strip of sheet product, so that the step of cutting the
web results in strips having a perforated side-cut at least at one
edge of the strip between two spaced perforation lines of the
respective strip.
[0027] Furthermore, a plurality of perforation lines may be spaced
in the machine feeding direction, wherein at least one perforated
segment and at least one non-cut segment are staggered in the
machine cross direction.
[0028] Except where express by context, it is intended that the
terms "across" or "extends across" contemplates not only those
embodiments having perforation lines that extend from one side to
the other of the web or strip but also those that extend
substantially from one side to the other of the web or strip.
[0029] It is one intention of the above method for manufacturing
strips of sheet product to provide for a reduction in the
perforation breaking strength of the strips of sheet product while
not adversely affecting the production constraints of the
manufacturing process, more specifically, to provide for a
decreased breaking strength of the strips of sheet product while
maintaining the yield and throughput of the production of the
strips from a web of sheet product while providing a web product
that provides for high or higher speed production rates relative to
a sheet product with continuous perforations extending across the
entire web.
[0030] Stated another way, the method of manufacturing a web of
sheet product according to the present invention provides for an
increase in the breaking strength of the web of sheet product while
feeding relative to a sheet product with continuous perforations
extending across the entire web, thereby reducing the risk of
breaking and maintaining the yield and throughput of the production
of the perforated web as an intermediate product. To overcome the
risk of breaking of the web while feeding it between the stages of
creating the perforation lines and, e.g., reeling the web to obtain
a log, perforated segments are only present along a portion of the
perforation line. Hence, the web is partially perforated along each
perforation line, wherein perforated segments and non-cut segments
are alternately arranged along the perforation line. This is
achieved by cutting the perforations in segments having a smaller
width than the web to be processed, such that the perforations are
cut only partially across the overall width of the web. The
breaking strength of the fed web is increased and the tension load
in the machine feeding direction of the web, which is necessary for
achieving a sufficient density of sheet product on the log, is
thereby substantially borne by the non-cut segment(s) along the
perforation line. Moreover, as the breaking strength is increased,
the above method allows for increased machine feed speed and has a
positive impact on the throughput of the manufacturing process.
Desirably, the web machine feed speed is at least 300 ft/min in the
present invention.
[0031] It may be provided that the length of the sheet product
between non-cut segments (in the machine direction) is larger by a
factor of two or more than the width of a non-cut segment.
[0032] It may be provided that the length of a perforated segment
is larger by a factor of two or more than the length of a non-cut
segment.
[0033] According to a further aspect, a method for manufacturing
strips of sheet product, in particular for use as paper towels,
napkins, hand tissues, facial tissues, toilet papers, kitchen
towels, hand towels, wipers, placemats, and the like, is provided.
The web has perforated segments the length of which is selected
such that the collective length of the at least one perforated
side-cut is between 1% to 20%, and more desirably 2% to 20%, of the
width of each strip of sheet product.
[0034] Generally, the web will be cut into strips after the web is
wound as a log, however, a slitter could also be used prior to
winding onto a roll. The cutting of the web may be carried out such
that each strip has a width that substantially corresponds to the
length of the perforated segments.
[0035] The length of the perforated segments may be selected such
that the collective or sum length of the perforated side-cuts for
each sheet product is greater than zero and less than 25%, and more
desirably between 1% and 20% of the width of each strip of sheet
product upon which the side-cut is located.
[0036] According to an embodiment, the bond ratio of a perforated
segment may be equal to or lower than 15%. Desirably, the bond
ratio is equal to or less than about 12%, and even more desirably
between about 4% and about 11%, including, but not limited to, bond
ratios of about 4.5%, about 5.5%, about 6.4%, about 7.2%, about
8.9%, and about 10.6% and ranges there between, wherein the bond
ratio in a given perforation section is a relation between the
non-cut portions and the overall length of the perforation
section.
[0037] Furthermore, the perforated segment may have at one or both
ends a perforation portion that has a bond ratio that differs from
the rest of the perforated segment.
[0038] The web may be provided with a separation cut or perforation
after the step of creating the offset perforated segments, wherein
the separation cut or perforation has a bond ratio that is adapted
to have a breaking strength which is lower than the breaking
strength of the perforation line.
[0039] After the perforating steps, the web can be reeled up to
form a log of sheet product, wherein the log may be severed to
obtain strips or rolls of sheet product. Alternatively, the strip
of sheet product may be folded along its longitudinal extension, so
that the sheets are stacked onto each other to form a sheet stack
(e.g., with napkins or towels).
[0040] According to a further aspect, a web of sheet product is
provided with spaced perforation lines transverse to its
longitudinal extension or orientation, wherein along each
perforation line the web has at least one perforated segment and at
least one non-cut segment that are alternately arranged along the
perforation line, wherein at least one perforated segment has a
perforation with a repeating pattern of cuts or perforation
portions and connecting tabs or non-cut portions, and wherein the
web has a breadth of at least three strips, each strip having a
predetermined width, each perforated segment being associated with
one or more of the strips to be disposed from the web, at least two
adjacent perforated segments along the same perforation line
extending across the respective strip width of web in a direction
transverse to the longitudinal extension, and further extending
along the web of sheet product to create perforated side-cuts, and
wherein the perforated side-cuts have a length of between 1% to
25%, and more desirably 4% to 20%, of the predetermined strip
width.
[0041] According to a further aspect, a source of sheet product for
use in a dispenser is provided including a strip of sheet product
having sheets connected by an unbroken perforation line or
perforation segment, wherein perforated side-cuts are provided
along a longitudinal extension of the strip at least at one edge of
the strip.
[0042] Moreover, the perforated side-cuts may be arranged between
two spaced perforation lines along a longitudinal extension of the
strip, desirably equally spaced from the perforation lines.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Other features and advantages of the present invention will
become apparent when reading the following detailed, yet not
limiting, description, for the understanding of which reference
will be made to the attached drawings, in which:
[0044] FIG. 1 schematically illustrates the process of forming or
cutting perforations into a fed paper web and its reeling up to
form a log;
[0045] FIG. 2 shows a basic view of an unwound web including
perforations resulting from the manufacturing method according to
an embodiment;
[0046] FIG. 3 shows a basic view of an unwound paper strip
including perforations resulting from the manufacturing method
according to an embodiment; and
[0047] FIG. 4 shows an alternate perforation arrangement wherein
perforation lines disposed on the web are skewed relative to the
machine direction of the web as they extend across the web.
DESCRIPTION OF EMBODIMENTS
[0048] Reference in detail will now be made to non-limiting
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
number has been used throughout the drawings and the following
detailed description to refer to the same or similar parts.
[0049] FIG. 1 is a schematic representation of a portion of a
manufacturing system 1 for producing a roll of sheet product from a
basic web 5 of sheet product and further illustrates a method for
manufacturing strips 13 of sheet product. The web of sheet product
may, e.g., be a paper web 5 made of absorbent paper used for paper
towels, napkins, hand tissues, facial tissues, toilet papers,
kitchen towels, hand towels, wipers, placemats, and the like. As an
alternative to paper, any woven or non-woven absorbent material
that is suitable to serve as a cleaning or drying sheet, or any
non-absorbent material that is suitable to serve as a cleaning or
drying sheet may be used. FIG. 2 shows a basic view of a perforated
paper web produced by the manufacturing system 1 before the paper
web 5 is severed to produce the source of paper sheets to be
accommodated in a dispenser. FIG. 3 shows a plain view of an
unwound paper strip 13 produced by the manufacturing system 1
before the paper strip 13 is rewound or folded to produce the
source of paper sheets to be disposed in a dispenser.
[0050] The manufacturing system 1 comprises a cutting head unit 2
through which the paper web 5 is passed in a machine feeding
direction F in order to provide it with perforated segments 18
along perforation lines 10. The illustrated cutting head unit 2 has
a rotary head 3 and a stationary perforating head 4. As
illustrated, the stationary perforating head 4 is provided with a
perforation blade 41, and the rotary head 3 is provided with a
plain blade 31, which are both illustrated in a larger scale at the
upper left of FIG. 1. It will be appreciated that in other
embodiments, the stationary head 4 may be provided with a plain
blade 31, and the rotary head 3 may be provided with a perforation
blade 41.
[0051] Each perforation blade 41 is comprised of non-perforating or
non-cutting blade portions 6 and perforating blade portions 7 which
define the pattern of the perforations. As shown in FIGS. 2 and 3,
perforations on the web 5 are alternately arranged tab or non-cut
portions 16 and cut or perforated portions 17 that are created by
the cutting head unit 2 as it rotates and the plain blade 31
contacts the perforation blade 41. Perforation as used herein is
defined as an alternating, repeating or randomized pattern of a
plurality of cut portions 17 and a plurality of tab or non-cut
portions 16.
[0052] The perforations may be alternating or repeating in nature
(e.g., A-B-A-B or A-B-C-A-B-C, A-B-B-A, A-B-C-C-B-A). It should be
appreciated that while alternating or repeating patterns of
perforations may be desirable, the present invention is also
intended to include randomized perforation patterns so long as the
overall bond percent or ratio is satisfied. For convenience of
discussion herein, randomized perforation patterns will be included
in the terms "repeating" or "alternately arranged."
[0053] The characteristics of perforations can be defined by its
bond ratio and the individual bond widths. The bond ratio is
defined by the summed lengths L of each tab or non-cut portions 16
within a total length T of a given perforation segment 18. In other
words, the bond ratio in a given perforation segment is a relation
between the non-cut portions 16 to the overall length of the
perforated segment 18. Based on the disclosure herein, it will be
appreciated that some variation in the calculation of the bond
ratio may result depending on the presence (or lack thereof) of a
fading perforation portion and whether the segment is measured as
formed or as cut. For purposes of this disclosure, bond ratios are
measured within a perforation segment 18. To the extent a fading
perforation portion is present at one or both ends of the
perforation segment, the bond ratio calculation shall be calculated
excluding the fading perforation portions from the segment.
[0054] The bond ratio of the perforations produced by the cutting
head unit 2 is equal to or less than 20%. Desirably, the bond ratio
is equal to or less than about 15%, more desirably equal to or less
than about 12%, and more desirably between about 4% and about 11%,
including, but not limited to, bond ratios of about 4.5%, about
5.5%, about 6.4%, about 7.2%, about 8.9%, and about 10.6% and
ranges there between.
[0055] Furthermore, perforation step length P, which is the total
length of just one cut portion 17 and just one neighboring or
adjacent tab or non-cut portion 16 is desirably between 1 mm and 20
mm.
[0056] In the illustrated embodiment, the paper web 5 is fed
through the cutting head unit 2 at a certain speed while the rotary
head 3 is rotating. The perforation blade 41 in the stationary
perforating head 4 and the plain blade 31 in the rotary head 3
periodically strike, thereby cutting perforation lines 10 into the
paper web 5 with a predefined spacing D in the machine feeding
direction F. Thereafter, the paper web 5 is fed to a reeling stage
11 and reeled onto a core to obtain a paper log 8. If the paper log
8 has reached its final size it may be severed from the fed web 5
and then cut by a saw 9 or other suitable separating instrument to
obtain paper rolls or strips of a desired width W. Strip widths W
are generally uniform across a particular web, however, it will be
appreciated that the strip widths across a web may not all be the
same or none may be the same.
[0057] In the illustrated embodiment, the plain blades 31 of the
rotary head 3 are directed outwardly from a carrier 33 and are
equally spaced from each other regarding a circumferential
direction thereof. Each plain blade 31 extends along the axial
direction of the rotary head 3. When the plain blade is in the
rotary head, it is contemplated that one of two blade
configurations will be used. The first configuration has multiple
blades spaced at a fixed (no cut) interval, while the second
configuration utilizes a single blade with relief where no cut is
desired.
[0058] In the illustrated embodiment, the plain blades 31 are
arranged in blade segments 32; their width and their axial
positions on the web 5 depend on the desired widths W of the paper
rolls to be produced. Each blade segment 32 is desirably associated
with one paper strip 13 to be produced, and more preferably, one
paper strip 13 and at least a portion of one of the adjacent
neighboring paper strips 13 to be produced. While the rotary head 3
has a width corresponding to at least the width of the paper web 5
to be processed, the plain blades 31 arranged at circumferential
positions have reduced lengths in the axial direction of the rotary
head 3 so that they are adapted to only partially cut the web 5 at
the perforation lines 10 in perforated segments 18 along the
overall width of the paper web 5. The perforations are shown as
alternating along a perforation line 10 so that each perforated
segment 18 on the web 5 has at least one neighboring or adjacent
non-cut segment 19. Axially adjacent plain blades 31 are offset or
staggered with respect to a rotational direction, such that the
blades 31 do not cut a continuous perforation along the perforation
line 10 extending along the overall width of the paper web 5.
[0059] The plain blades 31 may have axial lengths which are each
slightly larger than the axial width of one respective segment 32
or an have multiple blades that when combined form an integral
piece having the axial width of one respective blade segment 32
they are associated to, such that sheets 12 of each of the paper
strips 13 are separated by a continuous perforation line 10
corresponding to the perforated segments 18.
[0060] The plain blades 31 of the rotary head 3 can be provided in
different configurations. The configuration shown in FIG. 1 shows
three plain blades 31 along the circumferential direction of each
blade segment 32, wherein the plain blades 31 for neighboring blade
segments 32 are offset such that one plain blade 31 is placed at a
circumferential position which is in between two plain blades 31
associated with a neighboring blade segment 32. The number of plain
blades 31 associated with one blade segment 32 can also be one,
two, three or more, depending on the rotation speed of the rotary
head 3, the feeding speed of the paper web 5 and the desired sheet
length of the single sheets 12 that form the strip 13 to be reeled
up on the paper roll. It will be appreciated that the term
"transverse" is intended to include perforation line(s) disposed
perpendicularly or substantially perpendicularly on a web or strip
relative to the machine direction, as well as perforation lines
disposed on a strip or web in a non-perpendicular fashion relative
to the machine direction. As such, FIG. 4 shows perforated segments
18 at an acute angle .alpha. from a line perpendicular to the
longitudinal orientation of the web 5.
[0061] In the illustrated embodiments, if the perforated segments
18 have a length that is larger than the width W of the strip 13
associated therewith, the perforated segments 18 will extend or
overlap a distance 0 into material which will ultimately form
another strip 13 from the web 5. In addition to other advantages,
the overlap perforation allows for manufacturing tolerances when
cutting the log 8 to obtain paper rolls. Thus, the step of cutting,
slitting, or sawing the web 5 may result in strips 13 with a
perforated side-cut 20 at least at one edge of the strip 13 between
two spaced perforation lines 10 of the respective strip 13.
[0062] Furthermore, wherein two adjacent perforated segments 18
along a perforation line 10 (with a non-cut segment there between)
overlap the intermediate non-cut segment 19 in a direction
transverse to the longitudinal extension, the collective length of
the overlapping perforations is desirably between 1% and 25% of the
width of the strip. More desirably, the combined length of the
side-cuts on a sheet is at least 4% but less than 20% of the sheet
or strip width W, and more desirably 5% to 16% of the strip width
W. The overlap length may be adapted to the usual tolerances of the
cutting equipment for cutting the log 8 into strips. One embodiment
of the present invention contemplates a tissue product where the
sheet is approximately 10.2 cm in width and wherein the perforated
side-cuts 20 extend inward approximately 1 cm for each side
edge.
[0063] The perforated side-cuts 20 may have a bond ratio equal to,
less than, or higher than the bond ratio of the perforated segment
18. According to one embodiment, each perforated segment 18 has a
length that is slightly more than the width of one strip 13,
wherein the bond ratio increases towards the ends of the perforated
segments 18 in a perforation fading portion. In other words the
bond ratio of the perforation fading portion would be higher than
the bond ratio of the rest of the respective perforated segment 18.
As discussed below, it will be appreciated that this may be
achieved by perforation bond gradient or a perforation at a fixed
ratio that differs from the adjacent portion of the perforated
segment. The perforation fading portion may have a width
substantially corresponding to the overlap O that forms the
side-cuts 20. The side-cuts 20 formed may thereby have reduced
visibility, making them less noticeable to a consumer. Moreover, in
an embodiment, the perforation step length (see e.g., non-cut
portion 16) of the perforation fading portion can be reduced to an
average of 0.5 to 5 mm.
[0064] In another embodiment, a lower fading perforation may be
desirable. To achieve a lower fading perforation portion, the
length of the individual perforations or cuts 17 may be shortened.
Alternatively, the length of the tabs 16 between the individual
perforations or cuts 17 may be lengthened thereby changing the
frequency of the individual perforations or cuts 17 along a
perforated segment 18. It will also be appreciated that the spacing
or size of perforation cuts 17 and/or tabs 16 may be uniform across
a perforation segment 18 or the cuts 17 and tabs 16 may vary. The
inventors of the present invention also discovered that the
location of one or more larger tabs 16 within a perforated segment
18 can provide increased perforation strength yet still allow for
the separation desired when dispensed.
[0065] As to the paper strips 13 so produced, sheets are connected
by an intact or unbroken perforation line formed in part by the
perforated segments 18, wherein perforated side-cuts 20 are
provided along at least at one edge of the longitudinal extension
of the strip 13. The perforated side-cuts 20 may be arranged at the
ends of a perforated segment 18 along the longitudinal extension of
the strip 13. Since the side-cuts 20 are perforated but not fully
cut, folding of edges of the sheets in subsequent process stages
may be prevented, thereby maintaining high product quality.
[0066] The cutting of the paper log 8 may be carried out, e.g., by
way of a log saw in order to obtain paper rolls 13. Common widths
of the strips 13 of a napkin product obtained after cutting the log
8 are between 10 cm and 30 cm, desirably between 14 cm and 22 cm,
and most desired between 15 cm and 19 cm. The saw-cutting is
desirably performed within a position of the log 8 disposed within
the range of the overlap O. It will be appreciated that desired
strip widths may vary based on the type of product and/or its
intended use.
[0067] As shown in FIG. 2, to allow a separation of a log 8 (or
readily perforated web 5 of predetermined length) from the fed web
5 after the web 5 has been perforated with a predetermined length,
the web 5 can be provided with a separation perforation 15 after
the initial step of perforating. The separation perforation 15 is
typically made in addition to the cutting of the perforation lines
10. The separation perforation 15 desirably has a bond ratio that
is equal to or less than the bond ratio of the perforated segments
18. In particular, the bond ratio of the separation perforation 15
is equal to or less than 15%. More desirably, the bond ratio is
equal to or less than about 12%, and even more desirably between
about 4% and about 11%, including, but not limited to, bond ratios
of about 4.5%, about 5.5%, about 6.4%, about 7.2%, about 8.9%, and
about 10.6% and ranges there between. To make the separation
perforation 15 where the web 5 breaks when the tension force is
increased, the total breaking strength of the separation line 15
needs to be lower than the total breaking strength of the
perforation line 10 including the perforated and non-cut segments
18, 19, respectively.
[0068] As shown in FIGS. 1 and 2, the separation perforation 15
(FIG. 2) may be made by a further cutting tool 22 (FIG. 1) at a
stage before the web is wound up onto the log 8 (FIG. 1). The
cutting tool 22 has a perforation knife and an anvil knife that are
engaged to create the separation perforation 15, e.g., depending on
the length of web wound up on the log 8, repeatedly after a
predetermined number of perforation lines 10, periodically, or in
some similar fashion.
[0069] To fully separate the log 8 from the fed web 5, the feeding
of the web 5 may be slowed or shortly braked after the separation
perforation 15 is introduced. The fed web 5 may be slowed by a
rubber tool 23 or the like that is arranged between the log 8 and
the cutting tool 22. The rubber tool 23 may briefly engage the fed
web 5 just after the separation perforation 15 has passed through
such that a separation force is applied to the separation
perforation 15 to break it. The action of the rubber tool 23 should
be synchronized with the action of the cutting tool 22.
[0070] The separation force results from continuously winding up
the paper web 5 to the log 8 with the machine feeding speed and the
sudden stop applied on the fed web 5 by the rubber tool 23 such
that the separation force leads to the breaking of the web at its
weakest position, along the separation perforation 15. The
separation perforation 15 avoids, when applying the separation
braking, the web breaking irregularly along the perforated segments
18 leading to a skewed, non-straight separation edge.
[0071] In an alternative embodiment, the rotation of the log 8 can
be briefly accelerated after the separation perforation 15 is made,
thereby applying an increased tension force onto the web resulting
in a breaking along the separation perforation 15.
[0072] The separation perforation 15 may be aligned with the
perforation lines 10; however, in some manufacturing processes, it
is desirable that the separation perforation 15 not be aligned with
the perforation lines 10 so that the separation perforation 15 does
not have such a low breaking strength that breaking may occur
before separation is intended (e.g., the rubber tool is applied).
In another embodiment, it is contemplated that a distance of sheet
product prior to the end of production roll would not have any
perforations on the outermost layer or layers so as to avoid
unintentional tearing during the log cutting and/or transfer of the
log.
[0073] The above manufacturing process allows the production of
rolls of sheet product having a significantly reduced bond ratio
with no substantial impact on the density of the strip rolls and
the reliability of the manufacturing process. The reduced bond
ratio substantially decreases the breaking force necessary to tear
a sheet off the strip, which allows omitting or substantially
reducing the friction or other opposing force intentionally
embodied in conventional dispensers.
[0074] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
REFERENCE LIST
[0075] 1 manufacturing system [0076] 2 cutting head unit [0077] 3
rotary head [0078] 4 stationary perforation head [0079] 5 web
[0080] 6 cutting blade portion [0081] 7 non-cutting blade portion
[0082] 8 log [0083] 9 log saw [0084] 10 perforation line [0085] 11
reeling stage [0086] 12 sheet [0087] 13 strip [0088] 15 separation
perforation [0089] 16 tab or non-cut portions [0090] 17 perforated
portions [0091] 18 perforation segments [0092] 19 tab or non-cut
segments [0093] 20 side-cut [0094] 22 cutting tool [0095] 23 rubber
tool [0096] 31 plain blades [0097] 32 blade segment [0098] 33
carrier [0099] 41 perforation blade [0100] O overlap [0101] F
machine feeding direction [0102] D spacing [0103] W width of strip
[0104] L length of non-cut portion [0105] T total length of a given
perforation section [0106] P perforation step length
* * * * *